CVE-2026-48523 PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys

PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode or jwt.decodecomplete are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature...

CVE-2026-48523

PyJWT vulnerability affecting versions 2.9.0–2.12.1 where verifier-side algorithm allow-list bypass occurs when decoding with a PyJWK/PyJWKClient key. The token header’s alg is checked against the caller-supplied allow-list, but the signature is verified using the algorithm bound to the PyJWK obj...

CVE-2026-48524

CVE-2026-48524 affects PyJWT prior to 2.13.0. The issue is in PyJWKClient.get_signing_key(), which can force a fresh HTTP request to the JWKS endpoint for every JWT with an unknown kid value, with no rate limiting. Since the kid is from an unverified token header, an attacker can trigger unlimite...

CVE-2026-48524 PyJWT: PyJWKClient unbounded JWKS endpoint requests via attacker-controlled kid values (DoS)

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient.getsigningkey forces a fresh HTTP request to the JWKS endpoint for every JWT with an unknown kid value, with no rate limiting. Since kid comes from the unverified token header, an attacker can trigger unlimited...

CVE-2026-48522 PyJWKClient: missing scheme allowlist enables SSRF + token forgery via file://, ftp://, data: schemes

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient passes its uri argument directly to urllib.request.urlopen which uses Python stdlib's default OpenerDirector registering HTTPHandler, HTTPSHandler, FTPHandler, FileHandler, and DataHandler. There is currently no...

PT-2026-44394

Name of the Vulnerable Software and Affected Versions PyJWT versions prior to 2.13.0 Description PyJWKClient passes the uri argument directly to urllib.request.urlopen, which utilizes the default OpenerDirector of the Python standard library. This allows the registration of HTTPHandler,...

CVE-2026-48522: Unintended Proxy or Intermediary

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient passes its uri argument directly to urllib.request.urlopen which uses Python stdlib's default OpenerDirector registering HTTPHandler, HTTPSHandler, FTPHandler, FileHandler, and DataHandler. There is currently no...